diff --git a/miosix/arch/cpu/armv7m/interfaces-impl/userspace_impl.h b/miosix/arch/cpu/armv7m/interfaces-impl/userspace_impl.h
index b0fcfcd8906ed991a4b4891a6b5c0d563df2a2c3..1bb1dcdbc821a8bc0d58538589ca8be8f2d535d3 100644
--- a/miosix/arch/cpu/armv7m/interfaces-impl/userspace_impl.h
+++ b/miosix/arch/cpu/armv7m/interfaces-impl/userspace_impl.h
@@ -136,7 +136,9 @@ inline void MPUConfiguration::IRQdisable()
 inline void IRQenableMPUatBoot()
 {
     #if __MPU_PRESENT==1
-    MPU->CTRL=MPU_CTRL_PRIVDEFENA_Msk | MPU_CTRL_ENABLE_Msk;
+    MPU->CTRL = MPU_CTRL_HFNMIENA_Msk
+              | MPU_CTRL_PRIVDEFENA_Msk
+              | MPU_CTRL_ENABLE_Msk;
     #endif //__MPU_PRESENT==1
 }